Shower pipes are generally known and are used in paper machines for cleaning fabrics, press felts, roll covers, suction rolls, etc. There are various designs regarding the manner in which the nozzles are fitted. Certain shower pipes comprise a plurality of nozzle devices which are equally spaced along the longitudinal axis of the pipe and each nozzle device itself comprises a cylindrical body having an outer thread and an inner hexagon socket, a gasket element and a disk-like nozzle insert with a cylindrical passage or channel. To mount the nozzle devices at the shower pipe, the shower pipe comprises threaded openings in which the gasket element and the nozzle insert are inserted and fixed by screwing the cylindrical body into the opening. In FIG. 6 of the attached drawings, a known shower pipe is shown.
During operation of the shower pipe, it is supplied with water at high pressure which passes through the cylindrical passages of the nozzles toward the fabrics, press felts, etc. to be cleaned.
In FIGS. 4 and 6 of the attached drawings, the nozzle device of the prior art is shown in detail. As already mentioned, the known nozzle device comprises a cylindrical body which is provided as a threaded retainer ring 3, a gasket element 4 and a nozzle insert which is provided as a nozzle disc 5.
The nozzle device comprised of these three elements is fixed at the shower pipe 1 within a threaded opening 2. Particularly, for mounting the nozzle device it is first necessary to insert the gasket element 4 which is supported by an annular flange within the opening 2. Second, the nozzle disc is inserted and third, the unit of gasket and nozzle disc is fixed with the retainer ring 3 screwed into the opening 2. Hence, the nozzle disc 5 is sandwiched between the gasket element and the retainer ring. For screwing the retainer ring, it is provided with a hexagonal socket. As to allow a 110° fan jet, as shown in FIG. 4, the socket has a limited depth.
Due to this limited depth of the retainer ring, it is difficult to guarantee a secure engagement with an Allen key, particularly in cases where the retainer ring has to be unscrewed after a long period of operation.
A further disadvantage of the nozzle devices as shown in FIGS. 4 and 6 is that it is difficult for the mechanic installer to handle the three parts of the nozzle device. This disadvantage is of particular concern as the shower pipe extends along the total width of a felt of a paper machine and, therefore, comprises a great number of such nozzles. The effort to install all these nozzles or to change them is substantial. Objects lost in the machine represent a significant danger of extensive damage during startup or operation of the machine.
A further problem with the known nozzle devices is that the risk that an element of the nozzle device falls into the paper machine is high.